Unlike mitosis, meiosis in male mammals results in the formation of

• one haploid gamete
• three diploid gametes
• four diploid gametes
• four haploid gametes

Tags

NGSS.HS-LS3-2

A human zygote should have _____ chromosomes inside.

• 46
• 23
• 92
• 64

Tags

NGSS.HS-LS3-2

When an area of a chromatid is exchanged with the matching area on a chromatid of its homologous chromosome, _________________ occurs

• crossing over
• mutagenesis
• hybridization
• fertilization

Tags

NGSS.HS-LS3-2

If a body cell in a butterfly contains 24 chromosomes, a butterfly egg would contain

• 3
• 6
• 12
• 24

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

A single gene mutation results from

• a change in a base sequence in DNA
• recombination of traits
• the failure of chromosomes to separate
• blocked nerve messages

Tags

NGSS.HS-LS3-2

Which statement best describes a chromosome?

• It is a gene that has thousands of different forms.
• It has genetic information contained in DNA.
• It is a reproductive cell that influences more than one trait.
• It contains hundreds of genetically indentical DNA molecules.

Tags

NGSS.HS-LS3-1

In the F1 generation of 915 pea plants, there were 716 tall plants and 199 short plants. Tall is dominant over short. What was the parental cross?

• tt xtt
• Tt x Tt
• TT x tt
• Tt x tt

Tags

NGSS.HS-LS3-1

The fourth child in the F2 generation has Down syndrome. Which of the following statements represents a reasonable explanation for the appearance of this syndrome the third generation when it is not expressed in the P1 or F1 generations?

• Down syndrome is a recessive trait and was passed down through the generations but not expressed.
• Down syndrome is caused by a dominant allele that becomes active under a limited set of environmental conditions.
• Down syndrome is the result of an alteration of the chromosome number and was not passed from P1 to F1 to F2.
• Down syndrome is a sex linked trait expressed in the fourth F2 child because this male possesses a single X chromosome.

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

In certain rats, black fur is dominant over white fur. If two rats, both heterozygous for fur color are mated, their offspring would be expected to have 

• four different genotypes and two different colors
• two different genotypes and three different colors
• three different genotypes and two different colors
• three different genotypes and three different colors

Tags

NGSS.HS-LS3-1

NGSS.HS-LS3-2

NGSS.HS-LS3-3

Which of the following genotypes is homozygous recessive?

• RR
• Rr
• rr
• None of the Above